Who listens?

Dr. Jones, a young psychiatrist begins his practice in an office building.
After several weeks, he realizes that the older man he usually sees in the
elevator each morning and evening is Dr. Smith, also a psychiatrist. Finally,
after a month or two of frequently sharing the elevator, Dr. Jones pulls his
skewed tie, rakes his fingers through his disarrayed hair and approaches his
colleague: "Dr. Smith," he says. "Every day I step into this elevator in the
evening, exhausted and frazzled by the gut-wrenching stories of my patients, and
you appear as calm and cool as you do each morning. Tell me; tell me please how
to do it? How do you maintain your equanimity after listening to the woes of
your patients?" "My dear Dr. Jones," replied the older man. "Who listens?"